1. Technical Field
The invention relates generally to wireless communication systems; and more particularly to a wireless communication system and an associated method of operation in which radio resources are dynamically allocated to reduce system interference within the wireless communication system.
2. Related art
A wireless communication system is generally known in the art to service wireless communications with wireless mobile units operating within a respective service area. The construction of a wireless communication system typically includes a plurality of base stations dispersed throughout the service area. The base stations couple to base station controllers, with each base station controller serving a plurality of base stations. Each base station controller couples to a mobile switching center that also couples to the public switched telephone network and to other mobile switching centers. When being serviced, the mobile units establish wireless communications with one or more of the base stations.
The wireless communication system operates within an allocated frequency band. The allocated frequency band is subdivided into a plurality of channels with each channel occupying a respective bandwidth of the frequency band. Each of the base stations is allocated at least one channel in which all communications with proximate mobile units are carried. In most wireless communication systems, each base station supports a plurality of sectors, with each sector allocated at least one channel. Allocation of channels is performed so that the base stations can adequately service each of the mobile units operating in their proximity.
The capacity of prior wireless communication systems was fixed. Base stations and the supporting infrastructure was initially installed and channels were assigned to service a projected loading across the systems. As loading increased, additional base stations were installed and/or additional channels were allocated to existing base stations to service the additional load. Such initial allocations and subsequent additional allocations for each cell/sector were made to serve a peak loading interval for the respective cell/sector.
However, loading patterns do not correspond to the fixed capacity of prior wireless communication systems. As is known, loading across any wireless communication system varies significantly by time of day and day of week with such loading patterns not being proportional across the system. Some portions of the system are more heavily loaded during working hours, some during evening hours, some during commuting hours and some over the weekend. Thus, because resources within the wireless communication system are deployed to meet the greatest loading period for each base station/sector within the wireless communication system, substantial resources remain unused during most loading periods. These allocated resources are extremely expensive and, when not fully used to service calls, generate no revenue for the service provider. Further, when additional channels are allocated, system interference is increased. Thus, it has been advantageous for most operators of wireless communication systems to deploy minimal resources that provide a minimal acceptable service quality during most time periods but unacceptable service quality during peak loading periods.
Thus, there is a need in the art for a wireless communication system and method of operation that manages resources to assign resources when capacity is needed, does not assign the resources when they are not needed, and manages such assignments to minimize interference within the system to maximize grade of service.